The present invention concerns a method and a device for displaying data relating to the meteorological environment of the aircraft on a screen on the flight deck of said aircraft.
It is known that, notably on transport aircraft, such a display is generally provided on navigation screens, namely of the ND (Navigation Display) type in the lateral plane, and of the VD (Vertical Display) type in the vertical plane.
It is also known that a navigation screen of the ND type provides the crew with all the medium and short term data concerning the environment, in order to present the pilots with a lateral navigation status of the aircraft linked with the flight plan. The ND screen also includes several layers of data that the crew can display successively on demand, and notably:                meteorological data sourced from a weather radar on board the aircraft;        terrain data sourced either from an onboard database, or from an onboard weather radar through a particular operating mode of the weather radar;        airport navigational data; and        a data set linked notably to traffic management and certain warnings.        
The display of environmental data inside the flight deck is supplemented by a vertical display supported by the VD screen in order to offer the pilot an additional means of analyzing the environment. The VD screen displays the current position of the aircraft in relation to safe altitudes, the weather, the terrain and the flight path.
The VD screen takes account of a set of vertical sections along the flight path of the aircraft in order to display the terrain, the weather and the safe altitudes. These vertical sections can be defined along the flight plan, along the current flight path or along an azimuth selected at the weather radar.
Furthermore, the onboard radar usually offers the crew different functions to assist them in their tasks of analyzing the meteorological environment in the short and medium term, and notably:                a meteorological display function;        a wind shear prediction function;        a turbulence detection function; and        a terrain mapping function.        
The weather radar detects precipitation in a region ahead of the aircraft through a radar antenna. It moreover continuously scans this volume and stores it in a buffer memory. An extract sourced from this buffer memory is then used to create the display on the ND screen or on the VD screen.
Furthermore, a weather display functionality is known, which allows the pilot to see water precipitation through different levels of intensity symbolized by a corresponding color code. Moreover, several additional functions are usually available for controlling the weather display on the ND screen and on the VD screen, in order to offer the pilots greater flexibility in their analysis of the weather along the horizontal and/or vertical axes.
The weather radar, through the image of horizontal (ND) and vertical (VD) sections, participates in the creation of representations of the meteorological environment, facilitating comprehension thereof. Likewise, warnings with color coding and certain particular geometric shapes allow communication to the crew of the different levels of danger associated with the meteorological environment perceived by the radar antenna.
However, the representations displayed on the ND screen and the VD screen reach a certain limit of utilization when the pilot tries to understand the meteorological environment in a three-dimensional manner, since he must reconstitute this space ahead of the aircraft from a succession of images, using the different modes of the weather display. The representations, displayed in automatic mode on the ND screen and the VD screen, are a fusion of several horizontal and vertical sections.
Consequently, in order to obtain a more detailed representation without fusion, the pilot must perform several scans in one direction then in the other in order to understand how the cloud mass or masses develop around the aircraft. Now, this method requires significant cognitive resources for the duration of this analysis (which can be longer or shorter depending on the context). Moreover, the quality of the reconstruction of this mental image in three dimensions requires a non-negligible skill in the combined use of the ND and VD screens and of the display modes.